<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>

</head>
<body>
    <div>111</div>

<script>
    var div = document.getElementsByTagName("div")[0];

    div.onclick = fn;

    function fn() {
        alert(1);
    }

    //第二种属性绑定
//    div["onclick"] = function () {
//        alert(2);
//    }

//    console.log(div.onclick);
//    console.log(div.onmouseover);

    div.removeEventListener("click",fn);


</script>
</body>
</html>